From: Thierry Reding <thierry.reding@gmail.com>
To: Hans de Goede <hdegoede@redhat.com>
Cc: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
"Jani Nikula" <jani.nikula@linux.intel.com>,
"Joonas Lahtinen" <joonas.lahtinen@linux.intel.com>,
"Rodrigo Vivi" <rodrigo.vivi@intel.com>,
"Ville Syrjälä" <ville.syrjala@linux.intel.com>,
"Rafael J . Wysocki" <rjw@rjwysocki.net>,
"Len Brown" <lenb@kernel.org>,
linux-pwm@vger.kernel.org,
intel-gfx <intel-gfx@lists.freedesktop.org>,
dri-devel@lists.freedesktop.org,
"Andy Shevchenko" <andriy.shevchenko@linux.intel.com>,
"Mika Westerberg" <mika.westerberg@linux.intel.com>,
linux-acpi@vger.kernel.org
Subject: Re: [PATCH v9 07/17] pwm: lpss: Remove suspend/resume handlers
Date: Thu, 3 Sep 2020 13:00:12 +0200 [thread overview]
Message-ID: <20200903110012.GB3756465@ulmo> (raw)
In-Reply-To: <20200903105114.9969-8-hdegoede@redhat.com>
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On Thu, Sep 03, 2020 at 12:51:04PM +0200, Hans de Goede wrote:
> PWM controller drivers should not restore the PWM state on resume. The
> convention is that PWM consumers do this by calling pwm_apply_state(),
> so that it can be done at the exact moment when the consumer needs
> the state to be stored, avoiding e.g. backlight flickering.
>
> The only in kernel consumers of the pwm-lpss code, the i915 driver
> and the pwm-class sysfs interface code both correctly restore the
> state on resume, so there is no need to do this in the pwm-lpss code.
>
> More-over the removed resume handler is buggy, since it blindly
> restores the ctrl-register contents without setting the update
> bit, which is necessary to get the controller to actually use/apply
> the restored base-unit and on-time-div values.
>
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> ---
> drivers/pwm/pwm-lpss-platform.c | 1 -
> drivers/pwm/pwm-lpss.c | 24 ------------------------
> drivers/pwm/pwm-lpss.h | 3 ---
> 3 files changed, 28 deletions(-)
Nice!
Acked-by: Thierry Reding <thierry.reding@gmail.com>
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next prev parent reply other threads:[~2020-09-03 11:15 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-03 10:50 [PATCH v9 00/17] acpi/pwm/i915: Convert pwm-crc and i915 driver's PWM code to use the atomic PWM API Hans de Goede
2020-09-03 10:50 ` [PATCH v9 01/17] ACPI / LPSS: Resume Cherry Trail PWM controller in no-irq phase Hans de Goede
2020-09-03 10:50 ` [PATCH v9 02/17] ACPI / LPSS: Save Cherry Trail PWM ctx registers only once (at activation) Hans de Goede
2020-09-03 10:51 ` [PATCH v9 03/17] pwm: lpss: Fix off by one error in base_unit math in pwm_lpss_prepare() Hans de Goede
2020-09-03 10:51 ` [PATCH v9 04/17] pwm: lpss: Add range limit check for the base_unit register value Hans de Goede
2020-09-03 10:51 ` [PATCH v9 05/17] pwm: lpss: Add pwm_lpss_prepare_enable() helper Hans de Goede
2020-09-03 10:51 ` [PATCH v9 06/17] pwm: lpss: Make pwm_lpss_apply() not rely on existing hardware state Hans de Goede
2020-09-03 10:59 ` Thierry Reding
2020-09-03 11:12 ` Hans de Goede
2020-09-03 10:51 ` [PATCH v9 07/17] pwm: lpss: Remove suspend/resume handlers Hans de Goede
2020-09-03 11:00 ` Thierry Reding [this message]
2020-09-03 10:51 ` [PATCH v9 08/17] pwm: crc: Fix period / duty_cycle times being off by a factor of 256 Hans de Goede
2020-09-03 10:51 ` [PATCH v9 09/17] pwm: crc: Fix off-by-one error in the clock-divider calculations Hans de Goede
2020-09-03 10:51 ` [PATCH v9 10/17] pwm: crc: Fix period changes not having any effect Hans de Goede
2020-09-03 10:51 ` [PATCH v9 11/17] pwm: crc: Enable/disable PWM output on enable/disable Hans de Goede
2020-09-03 10:51 ` [PATCH v9 12/17] pwm: crc: Implement apply() method to support the new atomic PWM API Hans de Goede
2020-09-03 10:51 ` [PATCH v9 13/17] pwm: crc: Implement get_state() method Hans de Goede
2020-09-03 10:51 ` [PATCH v9 14/17] drm/i915: panel: Add get_vbt_pwm_freq() helper Hans de Goede
2020-09-03 10:51 ` [PATCH v9 15/17] drm/i915: panel: Honor the VBT PWM frequency for devs with an external PWM controller Hans de Goede
2020-09-03 10:51 ` [PATCH v9 16/17] drm/i915: panel: Honor the VBT PWM min setting " Hans de Goede
2020-09-03 10:51 ` [PATCH v9 17/17] drm/i915: panel: Use atomic PWM API " Hans de Goede
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